Control systems for regulating force between a drive roll and a yarn package driven by the roll are known. For example, Seney in U.S. Pat. No. 4,067,234 describes a strain transducer for measuring threadline tension in a moving threadline and a pneumatic control system responsive to the transducer for regulating the force between a drive roll in surface driven engagement with a threadline package and the package. Such systems unless operated at extremely slow rates produce severe hunting and because of this are unsatisfactory.
To circumvent this problem a negative feedback voltage generating bridge similar to that shown in Seney's U.S. Pat. No. 3,375,347 is used in connection with the strain transducer and a particular control system to assure that regulation of tension does not over or under shoot the set point by a wide margin.